Phosphors are essential materials in lighting, imaging and display applications. Extensive research has been carried out on rare earth activated oxide phosphors because of their superior color purity and good chemical and thermal stability. However, despite these efforts, examples of oxide phosphors with superior properties are very limited. Y.sub.2 O.sub.3 :Eu.sup.3+, discovered decades ago, is still the best red phosphor due to its high efficiency (97%), color purity (nearly single emission peak at .apprxeq.610 nm), and high thermal and chemical stability. It is currently used in tricolor lamps, field emission displays, projection TV displays, as well as other applications. The only drawback of Y.sub.2 O.sub.3 :Eu.sup.3+ is that its emission peak is around 610 nm (orange-red region), which does not completely satisfy the requirement of saturated colors in full color displays.
A major challenge in materials science is the development of new phosphors for advanced display technologies. Although the photophysical processes leading to luminescence are well understood, luminescence efficiencies and stabilities depend upon complex interactions between the host lattice, sensitizer and luminescent center. Consequently, the discovery and optimization of new phosphors is still highly empirical. Given its highly empirical nature, the discovery of new phosphors is well suited to combinatorial synthesis techniques.
The automated synthesis and rapid screening of large numbers of compounds is known in the art as combinatorial synthesis (see, PCT Publication No. WO 96/11878 incorporated herein by reference). Using combinatorial methods, thousands and even millions of new compounds can be synthesized in rapid fashion. It is then possible to survey a large number of compositions in combinatorial libraries seeking compounds with desirable physical-chemical characteristics.
There remains a need in the art for new phosphors and better and more efficient processes for their discovery. The present invention fulfills this and other needs.